642,420 research outputs found

    Correlated electrons and generalized statistics

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    Several important generalizations of Fermi-Dirac distribution are compared to numerical and experimental results for correlated electron systems. It is found that the quantum distributions based on incomplete information hypothesis can be useful for describing this kind of systems. We show that the additive incomplete fermion distribution gives very good description of weakly correlated electrons and that the nonadditive one is suitable to very strong correlated cases.Comment: 13 pages, RevTex file, 4 ps figures. The European Physical Journal B (2002), in pres

    Unnormalized nonextensive expectation value and zeroth law of thermodynamics

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    We show an attempt to establish the zeroth law of thermodynamics within the framework of nonextensive statistical mechanics based on the classic normalization Trρ^=1\texttt{Tr}\hat{\rho}=1 and the unnormalized expectation x=Trρ^qx^x=\texttt{Tr}\hat{\rho}^q\hat{x}. The first law of thermodynamics and the definition of heat and work in this formalism are discussed.Comment: 6 pages, no figure, RevTeX. To appear in Chaos, Solitons & Fractals (2002

    Extensive generalization of statistical mechanics based on incomplete information theory

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    Statistical mechanics is generalized on the basis of an additive information theory for incomplete probability distributions. The incomplete normalization i=1wpiq=1\sum_{i=1}^wp_i^q=1 is used to obtain generalized entropy S=ki=1wpiqlnpiS=-k\sum_{i=1}^wp_i^q\ln p_i. The concomitant incomplete statistical mechanics is applied to some physical systems in order to show the effect of the incompleteness of information. It is shown that this extensive generalized statistics can be useful for the correlated electron systems in weak coupling regime.Comment: 15 pages, 3 eps figures, Te

    Maximum path information and the principle of least action for chaotic system

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    A path information is defined in connection with the different possible paths of chaotic system moving in its phase space between two cells. On the basis of the assumption that the paths are differentiated by their actions, we show that the maximum path information leads to a path probability distribution as a function of action from which the well known transition probability of Brownian motion can be easily derived. An interesting result is that the most probable paths are just the paths of least action. This suggests that the principle of least action, in a probabilistic situation, is equivalent to the principle of maximization of information or uncertainty associated with the probability distribution.Comment: 12 pages, LaTeX, 1 eps figure, Chaos, Solitons & Fractals (2004), in pres

    Incomplete information and fractal phase space

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    The incomplete statistics for complex systems is characterized by a so called incompleteness parameter ω\omega which equals unity when information is completely accessible to our treatment. This paper is devoted to the discussion of the incompleteness of accessible information and of the physical signification of ω\omega on the basis of fractal phase space. ω\omega is shown to be proportional to the fractal dimension of the phase space and can be linked to the phase volume expansion and information growth during the scale refining process.Comment: 12 pages, 2 ps figure, Te
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